PushNav

Plate-Solving Push-To System for Manual Telescopes

A cross-platform plate-solving push-to system for manual telescopes. Add push-to navigation to a manual scope for about $50 in hardware you can order today.

Your laptop	USB camera + lens	Any manual telescope
macOS, Linux, or Windows. Runs on hardware you already own.	A specific $41 combo. A Waveshare OV9281 (~$26) plus a 25mm F2.4 M12 lens (~$15). Full BOM →	Dobsonian, manual EQ, or any push-around mount. No GOTO, no motors, no encoders.

PushNav uses a live camera feed to continuously plate-solve and determine where your telescope is pointing, reporting coordinates to Stellarium, SkySafari, and other planetarium apps in real time. Audio cues for lock, lost, and target alerts let you stay at the eyepiece without watching the screen.

PushNav is built around hardware you already own. The laptop you use every day handles the plate-solving and runs the desktop UI. The only new pieces are a USB camera and lens. That deliberate choice shortens the path to first light. You don't need to source, flash, configure, or troubleshoot a dedicated computer. The full desktop UI sits in one familiar window you can drag around on a table next to your scope. The live frame, Sky View dome, What to See catalog, and the planetarium-app servers are all on the same screen. A Raspberry Pi 4 headless appliance is on the roadmap, for observers who want a small dedicated box.

PushNav can also run completely standalone, without a separate planetarium app. Pick targets from its built-in What to See catalog. It offers a curated short-list of 161 hand-picked objects, a search across more than 20,000 stars and deep-sky objects, or a manual RA/Dec panel. Follow the push direction and watch your scope's pointing on the on-screen Sky View dome. The curated short-list is sourced from Stargazing Buddy, a companion observing guide by the same author.

What is plate-solving?

Any part of the night sky has a unique arrangement of stars. Plate-solving is a technique that takes a photo, matches that arrangement against a catalog, and reports exactly where the camera is pointing, down to a fraction of a degree. PushNav runs it continuously on the live camera feed, so the app always knows where your telescope is aimed.

PushNav uses the European Space Agency's (ESA) tetra3 fast lost-in-space plate solver, the same algorithm family that powers spacecraft navigation. This efficient solver produces near real-time solutions on a live video feed, enabling seamless push-to navigation even in light-polluted urban skies.

Above: PushNav in tracking mode. The right-hand Sky View dome shows the current pointing (yellow) and the active GOTO target (cream) on a hemispheric grid above the local horizon.

Push-to ops

Pick a target either inside PushNav or from any planetarium app you already use. PushNav's built-in "What to See" catalog covers a curated short-list, a fuzzy search across more than 20,000 stars and deep-sky objects, and a manual RA/Dec panel. Or stay in Stellarium on the desktop (or SkySafari, Stellarium Mobile, INDI, or ASCOM on a phone or tablet) and send the target from there. Either way, PushNav guides you to push the telescope to it, and your scope's live pointing moves on every connected app's sky chart in real time, staying in sync across all clients.

Above: M42 (Orion Nebula) is the active target on both Stellarium (desktop) and SkySafari (phone). As the scope is pushed, each plate-solve updates the telescope crosshair on every connected client simultaneously. No mount control, no GoTo motors. Just a camera and Wi-Fi.

Who is PushNav for?

PushNav is probably a good fit if most of these describe you:

• You own a manual telescope — Dobsonian, manual EQ, or any push-around mount with no GOTO motors or encoders.
• You have a laptop (macOS, Linux, or Windows) and you don't mind leaving it on a table or chair while you observe.
• You'd like to add push-to navigation to that scope for around $50, not the $300+ that comparable products typically cost.
• You observe from light-polluted skies where star-hopping is hard, and want a faster way to land on faint targets.
• You're OK with a brief one-time calibration at the start of each session (it takes under a minute after the first run).

Above: M45 (Pleiades) captured in a single PushNav frame from Bortle 8.5 Chennai, India. Invisible to the naked eye here, but clear on the sensor. Plate-solving works in heavy light pollution, not just dark skies.

If you already have a GOTO mount, or you want a phone-only experience with no laptop on hand, PushNav isn't the right tool — there are better-fitted products for those cases.

Cross platform from the ground up

Supports Windows, macOS, and Linux. The core app is written in Python, while the camera server is a native binary for each platform (Swift on macOS, C/V4L2 on Linux, C/DirectShow on Windows) to achieve maximum performance and compatibility with UVC cameras.

How It Works

1. Observer picks a target from PushNav's built-in What to See catalog, or from a planetarium app (Stellarium on the desktop, or SkySafari / Stellarium Mobile PLUS / INDI / ASCOM on a phone or tablet), and sends it to PushNav.
2. PushNav shows how to push the telescope to reach the target in its UI. A built-in mobile web interface lets you view the same guidance on your phone: scan a QR code and you're connected.
3. Your telescope's pointing shows in real time on the on-screen Sky View dome. When a planetarium app is connected, it also appears as a live crosshair on the app's sky chart, staying in sync across all clients.

Internal workflow

1. A USB camera in place of your telescope's finder captures the star field
2. PushNav plate-solves frames using the tetra3 star pattern recognition library in near real-time
3. The difference in pointing is calculated and translated into directional guidance which is shown in the UI
4. Solved RA/Dec coordinates are exposed to connected planetarium apps over standard telescope-control protocols, so your telescope's pointing moves on the app's sky chart in real-time as you push.

Features

• Near real-time plate solving (~20–140 ms per frame)
• One time, simple calibration. No named stars, just point at any bright star and sync
• GOTO navigation guidance for targets picked inside PushNav's What to See catalog or sent from your planetarium app (Stellarium, SkySafari, Stellarium Mobile, etc.)
• Works with SkySafari, Stellarium Mobile, INDI, and ASCOM clients over Wi-Fi via the LX200 protocol. See SkySafari & Other Apps
• Built-in "What to See" target picker — pick a target without leaving PushNav. Three modes: a curated Buddy catalog (161 hand-picked deep-sky objects with filters), an Advanced fuzzy search across 12,522 NGC objects and 8,825 bright stars, and Manual coordinates for anything else. See Using PushNav.
• Audio feedback for lock/lost/GOTO events
• Mobile web interface: scan a QR code on the PushNav screen with your phone for at-the-eyepiece push direction, no app install needed
• Always-visible Sky View — an interactive 3D hemispheric dome showing current pointing, the active target, and a small telescope marker on the pointing axis; visible during every step of the workflow.
• Saves calibration for quick re-sync
• Works from urban light-polluted skies with the right camera/lens combo (see hardware guide)

Open source: please report issues

PushNav is free and open source under the GPLv3. It's been tested in real observing sessions with Stellarium (desktop) and SkySafari Plus/Pro. The Stellarium Mobile, INDI, and ASCOM paths follow the same LX200 protocol and should work out of the box, but haven't yet been field-tested against every client version.

If something doesn't work as described (or you'd like to see an app supported that isn't listed), please open an issue on the GitHub issue tracker. Reports from real observing sessions are the best way for the project to improve.